Resilient soil composition for athletic fields

ABSTRACT

The soil composition of this invention is comprised of a mixture of sand, clay, a plasticizer material, water, and a coloring pigment, if desired. The components of the soil composition are preferably present in the following proportions by weight: sand 50-70%; clay 10-40%; plasticizer 0.5-5.0%; water 5-20%; and coloring pigment 1-5%. The method of making the invention involves continuously mixing a portion of the sand and the plasticizer in an agitation mixer. The same becomes coated with the plasticizer, whereupon a quantity of clay is then added, followed by an additional portion of the plasticizer material It is particularly important that the sand particles become coated with the plastizing compound and clay. The coloring pigments are added and mixed thereafter. As soon as complete mixing takes place, material can be immediately transferred from the mixer to suitable packaging.

This is a continuation of copending application Ser. No. 07/521,409filed on May 10, 1990, now U.S. Pat. No. 5,151,123.

BACKGROUND OF THE INVENTION

This invention arose from problem that developed in conjunction withmolded fiberglas baseball pitching mounds that had an indentedcompartment forwardly of the pitching rubber for the pitcher to steponto as the pitching motion was completed. That compartment normally wasfilled with a mixture of sand and clay, but that type of soilcomposition proved to be relatively unsatisfactory.

First of all, the combination of sand and clay did not drain or dry outvery easily. In addition, that soil composition, primarily because ofthe presence of the clay, would become very hard and had no resiliency.In addition, that soil composition was difficult to work or dress whensuch was necessary, and would adhere to the shoes of the pitcher.

It is therefore a principal object of this invention to provide a soilcomposition for athletic fields and the like which has good waterdraining and drying characteristics.

A further object of this invention is to provide a soil composition thatwill have resiliency and which will not become hard and packed uponeither drying or upon being stepped upon.

A further object of this invention is to provide a soil compositionwhich will not adhere to the footwear of persons walking or runningthereon.

A still further object of this invention is to provide a method ofmaking a soil composition which is not time consuming and which requiresno drying period.

A still further object of this invention is to provide a soilcomposition which can be easily worked and shaped.

A still further object of this invention is to provide a soilcomposition which can be changed to different colors by suitablepigments.

A still further object of this invention is to provide a soilcomposition that can be easily packaged and transported.

These and other objects will be apparent to those skilled in the art.

BRIEF SUMMARY OF THE INVENTION

The soil composition of this invention is comprised of a mixture ofsand, clay, a plasticizer material, water, and a coloring pigment, ifdesired. The components of the soil composition are preferably presentin the following proportions by weight: sand 50-70%; clay 10-40%;plasticizer 0.5-5.0%; water 5-20%; and coloring pigment 1-5%.

The method of making the invention involves continuously mixing aportion of the sand and the plasticizer in an agitation mixer. The sandbecomes coated with the plasticizer, whereupon a quantity of clay isthen added, followed by an additional portion of the plasticizermaterial. It is particularly important that the sand particles becomecoated with the plastizing compound and clay. The coloring pigments areadded and mixed thereafter. As soon as complete mixing takes place, thematerial can be immediately transferred from the mixer to suitablepackaging.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following tables show the preferred ingredients by weight of thesoil composition of this invention.

                  TABLE I                                                         ______________________________________                                        Ingredient            Range    Preferred                                      ______________________________________                                        Sand (Silicon Dioxide)                                                                              50-70%   60%                                            Polymer (Polyvinyl Alcohol)                                                                         0.5-5.0%  1%                                            Water (H.sub.2 O)      5-20%   11%                                            Clay (Hydrated Aluminum Silicate)                                                                   10-40%   26%                                            Coloring Pigment      1-5%      2%                                            ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        Ingredient            Range    Preferred                                      ______________________________________                                        Sand (Silicon Dioxide)                                                                              50-70%   60%                                            Polymer (Polyvinyl Alcohol)                                                                         0.6-5.0%  1%                                            Glycerol (Plasticizer)                                                                              0.2-3.0% 0.5%                                           Water (H.sub.2 O)      5-20%   11%                                            Clay (Hydrated Aluminum Silicate)                                                                   10-40%   25.5%                                          Coloring Pigment      1-5%      2%                                            ______________________________________                                    

Polyvinyl alcohol could be added or substituted with other polymerswhich possess plastizing properties. Other suitable plasticizers wouldbe polyvinyl acetate, polyvinyl chloride, or natural or synthetic rubberlatex, or glycerol.

The preferred method of making the soil composition of this inventioninvolves mixing the polyvinyl alcohol with water in the proportionsindicated to create a plasticizer in the form of a viscous-likesubstance. A quantity of sand is introduced into an agitation mixture,and a portion of the plasticizer is introduced into the mixer to coatthe sand. A portion of clay is then introduced into the mixer, whereuponplasticizer, sand and clay are introduced in turn in accordance with theabove proportions to complete the composition. Care should be exercisedto introduce the plasticizer following the introduction of additionalsand so that the sand particles can be coated with both the plasticizerand the clay. A suitable pigment, such as iron oxide, can be addedtowards the end of the mixing cycle.

The time for the mixing cycle is obviously variable depending upon thequantity of composition being mixed. It is also preferable that themixing take place at high speed to disperse the materials throughout themixture. The plasticizer can be sprayed into the mixer to facilitate theeven distribution thereof over the particles of sand.

As soon as the composition is suitably mixed, it can be immediatelytransferred to plastic bags or the like without any drying operation.

The resulting composition is pliable and can be easily worked to a givenshape. It will not become hardened, it dries easily, and it will notadhere to the spikes or shoes of the players.

The soil composition of this invention is a substantial improvement overthe prior use of clay, sand, or a mixture thereof. It has many usefulapplications on various types of athletic fields, walk ways, andinnumerable other environments.

It is therefore seen that this invention will achieve at least all ofits stated objectives.

I claim:
 1. A resilient soil composition for athletic fields which willnot become hard and packed upon either drying or being stepped upon,resulting from a method consisting of the steps of:taking a quantity ofsand comprised of sand particles; coating said sand particles with apremixed liquid plasticizer material comprised of polyvinyl alcohol,polyvinyl acetate, rubber latex and glycerol; adding a quantity of clayto the coated sand particles to form a coating of said clay on thecoated sand particles; and adding an additional outer coating of thepremixed liquid plasticizer on top of the sand particles coated with thecoating of said clay.